Fire Systems Maintenance and Fire Detection Systems Dwayne Smith Fire Protection Engineer
Introduction Overview of Regulatory Framework Act, Regulations and Codes Fire Protection Maintenance AS1851-2012 Tips and Tricks for maintenance FAQ Fire Detection System Design AS1670-2004 Unwanted alarm mitigation EWIS and Evacuation strategies
AS1851-2012 Current revision released in December 2012
Regulatory Framework QLD Building Act QLD Building Regulations QLD Development Code National Construction Code Series (BCA) Design Standards (e.g AS1670) Maintenance Standards - AS1851
Obligations Not required to comply with current design standards. Installation standards apply. Required to comply with the current maintenance standards.
Critical Defect? AS1851 now defines the level of a defect
Test Frequencies
Interface Testing Historically not captured very well, and in some cases not established at all Requires the testing of the interfaces between services, i.e smoke exhaust, stair press etc. Not intended as a commissioning test or retest.
Hospital Interface Testing Application of interface testing in a hospital can involve a significant number of services. Mechanical (stair press, smoke exhaust) Door releases Make up air Security BMS Public Address Gas shut off solenoids Pneumatic Tube
Testing Regimes It is often difficult to find records of testing other than weekly or monthly. 6 monthly, annual or more are rare. Instances in the past of significant sites in QLD with hydrant pipework which had not been hydrostatically or boost tested for 30 years. (5 yearly requirement). Another instance of a building which had a sprinkler system with no water in it for around 50 years. Annual testing would have picked this up.
Common Failures Underground pipework can deteriorate over time. Type B copper and Firelite were popular in the 1980 s, may not meet current requirements. Depending on water hardness, pipework may calcify an internal build up of calcium restricting flow. Water authorities are turning down water pressures in street mains to conserve water. From this, some systems no longer meet their requirements.
Internal conditions
Tips Consider an investigation into the underground pipework quality, and have it tested. Note, it may contain asbestos! Make sure you have a good clear block plan for sprinklers, detection and hydrants. Make sure that everything is labelled and corresponds with the block plan. Consider access safety to maintenance staff and QFRS is applicable, even though AS1851 doesn t mention it. Consider ESD initiatives hydrant and sprinkler test water can be captured and reused on site While we would recommend compliance with current standards, don t feel pressured into spending big money if you don t need to.
AS1670 Standard for fire detection and alarm systems (or is it?) AS1668, the standard for smoke control also applies. In hospitals, AS1670.4 (EWIS) is applicable as well. National Construction Code series drives the requirements for AS1670 detection.
National Construction Code Class 9a hospitals require full smoke detection to AS1670 regardless of height or size. The rise in storeys of a building drives the AS1668 fan control requirements. As an aside, sprinklers are required in any building greater than 25m in effective height, and may be provided in lieu of zone smoke control in a building with a rise in storeys of 3 or more. A full Emergency Warning and Intercommunication System (EWIS) is required for any hospital over 2 storeys or a floor area of more than 1000m 2
Detector Types Typical hospital detection types: Smoke Photoelectric or Ionisation type Heat fixed temperature or rate of rise Aspirated (Vesda) for critical areas such as server rooms, or where access is limited Fire Sprinklers Other detection devices covered by AS1670: Infrared Beam detection Linear Heat detection cable Other detection? Video smoke detection
System Types Two main types Addressable or Conventional In addressable systems, each detector has a unique address where it can be pinpointed by the FIP In conventional systems detectors are grouped into zones, identifies on the FIP as a zone rather than a detector. Conventional is generally being replaced with addressable.
General Intent of AS1670 Fire detection throughout the building every room, switchboards, lift shafts, risers. Additional fire detection is required in air handling units, stair press fans and the like Alarm tones are to be audible throughout
Specific Case Operating Theatre No special requirements under AS1670. A situation occurred in a hospital in New Zealand where a fire occurred in a plant room serving the theatre. Smoke was picked up by the Air Conditioning and dumped on top of the patient. As the smoke was cooled by the air, it didnt set off any detection in the room. There was no detection in the ventilation system. Patient had to be relocated mid operation once a manual alarm was raised.
Unwanted Alarm Mitigation Unwanted alarms are a nuisance to both the occupants and the fire brigade it ties up valuable resources. Smoke detectors can be triggered by dust, steam, or even invisible products of combustion. Areas in which false alarms are predicted (e.g kitchens) another detection device can be used instead of smoke detection usually a heat detector. The NCC considers a sprinkler to be the equivalent of a heat detector as they operate the same. In areas outside of patient care, it is possible to just delete a smoke detector altogether but note you lose the addressability function.
Emergency Warning and Intercommunication Systems Evacuation strategies in hospitals are a top priority due to the difficulty of mobilising patients. An EWIS allows full customisation of the system to maximise occupant discharge. This can be arranged such that alert and evacuate tones cascade radially occupants in the adjacent compartment are preparing to evacuate while the compartment of fire origin is evacuating. Warden intercommunication points, strobe lights, mimic panels and break glass alarms are also provided. Additional flexibility is afforded in the NCC for a reduction in alarm tone sound levels to suit the trauma of the patients.
Evacuation Strategy - Ipswich
Summary AS1670 drives the locations of detection and spacing requirements for full coverage. All of the building must be protected. Determines the requirements for detection type NCC permits the substitution of detectors to mitigate unwanted alarms AS1670.4 drives system requirements for a full EWIS to allow for orderly evacuation.